Field of the Invention
The present invention relates to a multi-lens optical apparatus to be used to perform multi-view image capturing, such as an image capturing apparatus and a lens apparatus.
Description of the Related Art
As a type of image capturing apparatuses such as video cameras and digital cameras, a multi-lens image capturing apparatus is proposed which has multiple divided imaging optical systems to realize miniaturization of the apparatus. Such a multi-lens image capturing apparatus utilizing a compound-eye structure of eyes of insects has, as the multiple imaging optical systems, for example, a lens array constituted by multiple lenses having small diameters and short focal lengths, which makes it possible to miniaturize the apparatus.
However, for such a multi-lens image capturing apparatuses, it is conventionally difficult to include an optical zooming function of varying an image-capturing field angle. This is because, for the multi-lens image capturing apparatus, employing the optical zooming function of varying the image-capturing field angle by moving lenses constituting the imaging optical systems in an optical axis direction, requires a mechanism to move each lens of each divided imaging optical system, which results in an increase in size of the image capturing apparatus.
Japanese Patent Laid-Open No. 2005-303694 discloses a multi-lens image capturing apparatus which includes a short-focal-length lens and a long-focal-length lens whose field angles are mutually different and which performs image capturing of an object such that a same area of the object is captured through the short-focal-length and long-focal-length lenses. This multi-lens image capturing apparatus inserts a zoom-up image acquired from an image-capturing area of an image sensor corresponding to the long-focal-length lens into part of an image acquired from an image-capturing area of the image sensor corresponding to the short-focal-length lens. Moreover, Japanese Patent Laid-Open No. 2001-330878 discloses an image capturing apparatus which includes multiple fixed-focal-length lenses whose focal lengths are mutually different and in which an image sensor is moved to a position on an optical axis of one fixed-focal-length lens to be used for image capturing to vary an image-capturing field angle of the apparatus.
Furthermore, Japanese Patent Laid-Open No. 2005-341301 discloses a multi-lens image capturing apparatus including multiple lens systems (optical systems) whose focal lengths are mutually different and which are each constituted by a front lens unit and a rear lens unit. In this multi-lens image capturing apparatus, a distance from a most object-side lens surface of the multiple lens systems is set such that a field of view of each lens system is not obstructed by the other lens systems.
Japanese Patent Laid-Open No. 2005-303694 discloses a configuration in which zooming is realized by performing image processing on images acquired through fixed-focal-length optical systems whose focal lengths are mutually different, but does not disclose a configuration to provide increased field angles of imaging optical systems required for expanding a zooming range. On the other hand, in the multi-lens image capturing apparatus disclosed in Japanese Patent Laid-Open No. 2005-341301, a lens surface of a wide-field-angle lens system among most object-side lens surfaces of the multiple lens systems is disposed at a position closest to the image sensor. For this reason, a further increase of a field angle of the wide-field-angle lens system causes obstruction of its field of view by a telephoto lens system.
Moreover, the image capturing apparatus disclosed in Japanese Patent Laid-Open No. 2001-330878 has a configuration in which the image sensor is moved with respect to the multiple fixed-focal-length lenses to switch the fixed-focal-length lens to be used for the image capturing. This configuration makes it impossible to use the image capturing apparatus as a multi-lens image capturing apparatus that simultaneously acquires multiple images whose field angles are mutually different.